Automatic document feeder

ABSTRACT

An automatic document feeder includes an upper cover, a sheet separation member and a crank. The sheet separation member includes a separation roller, a separation pad and a first elastic element. When the upper cover is opened, the upper cover is separated from the crank, and a first extension part of the crank is uplifted to push a second extension part of the separation pad, so that the separation pad is separated from the separation roller.

FIELD OF THE INVENTION

The present invention relates to an automatic document feeder, and more particularly to an automatic document feeder having an improved sheet separation structure.

BACKGROUND OF THE INVENTION

Various machines such as printers, scanners and faxing machines are common peripheral devices of a computer system. These machines are usually equipped with automatic document feeders.

FIG. 1 is a schematic cross-sectional view illustrating a conventional automatic document feeder. As shown in FIG. 1, the automatic document feeder 1 comprises a sheet-feeding channel 11 and a sheet separation structure 12. The sheet separation structure 12 comprises a separation roller 121, a separation pad 122, a base 123 and an elastic element 124. The separation pad 122 is attached on the surface of the base 123. The elastic element 124 is disposed under the base 123. Due to the elastic force provided by the elastic element 124, the separation pad 122 is tightly sustained against the separation roller 121. In this situation, a sheet separation function is achieved.

The sheet separation structure 12 of the automatic document feeder 1, however, still has some drawbacks. For example, in a case that the automatic document feeder 1 is suffered from a paper jam problem, the paper sheet in the sheet-feeding channel 11 will be clamped between the separation pad 122 and the separation roller 121. Meanwhile, the sheet separation function of the sheet separation structure 12 is lost. Since the separation pad 122 and the separation roller 121 are pressed by each other, it is difficult to remove the jammed paper sheet.

SUMMARY OF THE INVENTION

The present invention provides an automatic document feeder for facilitating the user to remove the jammed paper sheet. Due to the transmission relation between a crank and an upper cover of the automatic document feeder, the separation roller and the separation pad are either pressed by each other or separated from each other.

In accordance with an aspect of the present invention, there is provided an automatic document feeder. The automatic document feeder includes a casing, an upper cover, a sheet separation member and a crank. The sheet separation member includes a separation roller, a separation pad and a first elastic element. In response to an elastic force provided by the first elastic element, the separation roller and separation pad are pressed by each other. The crank is disposed under the upper cover. A first end of the crank is connected to the casing through a second elastic element. A first extension part is formed on a second end of the crank. When the upper cover is pressed down, the crank is pushed by the upper cover to be rotated in a first direction. Whereas, when the upper cover is opened, the upper cover is separated from the crank, the crank is driven by the second elastic element to be rotated in a second direction, and the first extension part of the crank is uplifted to push the second extension part of the separation pad, so that the separation pad is permitted to resist the elastic force of the first elastic element and separated from the separation roller.

In an embodiment, the crank has a slant surface. A pressing block is formed on a lower surface of the upper cover. When the upper cover is pressed down, the pressing block is contacted with the slant surface, so that the crank is rotated in the first direction.

In an embodiment, a notch is formed in the first extension part of the crank, and the second extension part of the separation pad has a tab, wherein the tab is inserted into the notch.

In an embodiment, the crank is L-shaped.

In an embodiment, the first elastic element is a compression spring.

In an embodiment, the second elastic element is a tension spring.

The above objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view illustrating a conventional automatic document feeder;

FIG. 2A is a schematic cross-sectional view illustrating an automatic document feeder according to an embodiment of the present invention, in which the upper cover of the automatic document feeder is in a close status;

FIG. 2B is a schematic cross-sectional view illustrating the automatic document feeder of FIG. 2A, in which the upper cover of the automatic document feeder is in an open status;

FIG. 3A is a schematic three-dimensional view illustrating the automatic document feeder of FIG. 2A; and

FIG. 3B is a schematic three-dimensional view illustrating the automatic document feeder of FIG. 2B.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention provides an automatic document feeder having the mechanism for eliminating the paper jam problem. FIG. 2A is a schematic cross-sectional view illustrating an automatic document feeder according to an embodiment of the present invention, in which the upper cover of the automatic document feeder is in a close status. FIG. 2B is a schematic cross-sectional view illustrating the automatic document feeder of FIG. 2A, in which the upper cover of the automatic document feeder is in an open status. Please refer to FIGS. 2A and 2B. The automatic document feeder 2 comprises a casing 21, an upper cover 22, a sheet separation member 23, a crank 24 and a second elastic element 25. The sheet separation member 23 is disposed under the upper cover 22. The sheet separation member 23 further comprises a separation roller 231, a separation pad 232 and a first elastic element 233. The separation roller 231 is disposed on a sheet pick-up arm 20. The separation pad 232 has a second extension part 234. In addition, the separation pad 232 is arranged between the separation roller 231 and the first elastic element 233. In this embodiment, the first elastic element 233 is a compression spring. In response to the elastic force T provided by the first elastic element 233, which is arranged under the separation pad 232, the separation roller 231 and the separation pad 232 are pressed by each other to avoid the multi feeding problem. As known, once the multi feeding problem occurs, two or more paper sheets are simultaneously fed into the sheet-feeding channel. The crank 24 is disposed under the upper cover 22. A first end of the crank 24 is connected to the casing 21 through the second elastic element 25. In this embodiment, the second elastic element 25 is a tension spring. Corresponding to the second extension part 234 of the separation pad 232, a first extension part 241 is formed on a second end of the crank 24.

Please refer to FIG. 2A, which illustrates the operating status of the crank 24 when the upper cover 22 is pressed down. When the upper cover 22 is pressed down, the crank 24 is pushed by the upper cover 22, so that the crank 24 is rotated in a first direction A. For allowing the upper cover 22 to smoothly press the crank 24, the crank 24 has a slant surface 242 at a tip thereof. Corresponding to the slant surface 242, a pressing block 222 is formed on a lower surface 221 of the upper cover 22. When the upper cover 22 is pressed down, the pressing block 222 is contacted with the slant surface 242, so that the crank 24 is rotated in the first direction A.

Please refer to FIG. 2B, which illustrates the operating status of the crank 24 when the upper cover 22 is opened. When the upper cover 22 is opened, the upper cover 22 is separated from the crank 24. In response to the restoring force of the second elastic element 25, the crank 24 is driven by the second elastic element 25 and thus rotated in a second direction B. Meanwhile, the first extension part 241 of the crank 24 is uplifted to push the second extension part 234 of the separation pad 232, so that the separation pad 232 is able to resist the elastic force T that is provided by the first elastic element 233. In this situation, the separation roller 231 and the separation pad 232 are separated from each other. In other words, if a paper jam problem occurs, the user may easily remove the jammed paper sheet.

Hereinafter, the relation between the crank 24 and the separation pad 232 will be illustrated with reference to FIGS. 3A and 3B. FIG. 3A is a schematic three-dimensional view illustrating the automatic document feeder of FIG. 2A. FIG. 3B is a schematic three-dimensional view illustrating the automatic document feeder of FIG. 2B. For clearly illustrating the position of the separation pad 232, the sheet pick-up arm 20 and the separation roller 231 are not shown in FIGS. 3A and 3B. As shown in FIG. 3A, the crank 24 is L-shaped. In addition, a notch 2411 is formed in the first extension part 241 of the crank 24. The second extension part 234 of the separation pad 232 has a tab 2341. The tab 2341 may be inserted into the notch 2411, so that the stability of connecting the first extension part 241 with the second extension part 234 will be enhanced. As shown in FIG. 3A, when the upper cover 22 is pressed down, the pressing block 222 of the upper cover 22 pushes the slant surface 242 of the crank 24, so that the crank 24 is rotated in the first direction A (see also FIG. 2A). In this situation, the crank 24 is no longer sustained against the separation pad 232. As shown in FIG. 3B, when the upper cover 22 is opened, the crank 24 is rotated in the second direction B (see also FIG. 2B). As such, the first extension part 241 of the crank 24 is uplifted, and then the tab 2341 is inserted into the notch 2411. In this situation, the separation pad 232 is pushed upwardly by the first extension part 241, so that the separation roller 231 and the separation pad 232 are separated from each other.

From the above description, the automatic document feeder of the present invention may facilitate the user to remove the jammed paper sheet. The purpose of removing the jammed paper sheet is achieved by installing the crank 24 in the automatic document feeder. Due to the transmission relation between the crank 24 and the upper cover 22, when the upper cover 22 is selectively opened or closed, the separation roller 231 and the separation pad 232 are either pressed by each other or separated from each other. As such, the jammed paper sheet may be removed without difficulty.

While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures. 

1. An automatic document feeder, comprising: a casing; an upper cover; a sheet separation member comprising a separation roller, a separation pad and a first elastic element, wherein in response to an elastic force provided by said first elastic element, said separation roller and separation pad are pressed by each other; and a crank disposed under said upper cover, wherein a first end of said crank is connected to said casing through a second elastic element, and a first extension part is formed on a second end of said crank, wherein when said upper cover is pressed down, said crank is pushed by said upper cover to be rotated in a first direction, wherein when said upper cover is opened, said upper cover is separated from said crank, said crank is driven by said second elastic element to be rotated in a second direction, and said first extension part of said crank is uplifted to push said second extension part of said separation pad, so that said separation pad is permitted to resist said elastic force of said first elastic element and separated from said separation roller.
 2. The automatic document feeder according to claim 1 wherein said crank has a slant surface, and a pressing block is formed on a lower surface of said upper cover, wherein when said upper cover is pressed down, said pressing block is contacted with said slant surface, so that said crank is rotated in said first direction.
 3. The automatic document feeder according to claim 1 wherein a notch is formed in said first extension part of said crank, and said second extension part of said separation pad has a tab, wherein said tab is inserted into said notch.
 4. The automatic document feeder according to claim 1 wherein said crank is L-shaped.
 5. The automatic document feeder according to claim 1 wherein said first elastic element is a compression spring.
 6. The automatic document feeder according to claim 1 wherein said second elastic element is a tension spring. 